This invention relates generally to interactive educational and entertainment systems, and more particularly to method and apparatus for data encoding a video signal at a remote broadcast site, decoding the signal at a reception site, and locally transmitting the data to control one or more interactive devices. The preferred embodiment of the invention is described in the context of television program control of toys located in a television viewer's home.
Videotext systems are known to be able to provide data communication from a remote video broadcast site to home television viewers over conventional broadcast channels. One such videotext system provides closed captioning of audio program material for the hearing-impaired, wherein the interpretive text is transmitted during vertical synchronization intervals of the raster scan process. Only televisions that are specially equipped with decoders are able to display the captions, and the displaying of video text in synchronization with the television's raster scan electronics requires the physical interconnection of the decoder and the television, e.g. an antenna hookup. Frequently, the payment of a subscription fee is required.
Attempts to provide systems capable of generalized, in-band data communications have met only marginal success. This is because conventional in-band signaling is disruptive of the television's video image. For example, when data and pixel information are mixed in the same video field or frame, they are spatially separated to enable a light sensitive detector unobtrusively to monitor the data-encoded subfield. Typically, this spatial separation is achieved by defining one or more cells, each of which is first blanked and then reprogrammed with high and low luminance regions representing binary coded data.
Depending upon the size, number and coding of such data cells, the effective viewing area of the video program material is more or less adversely impacted. Such video data communications systems do not lend themselves to conventional broadcast channels, where subscribing and nonsubscribing television receivers alike will display the composite pixel and data information. Visual clutter that is visible on the television screens of nonsubscribers, or on the screens of subscribers who are not using their light sensitive detector at the time, likely will result in consumer complaints and FCC restrictions.
It is desirable to provide an interactive video system capable of simplex data communications that is raster time-base error tolerant, and that requires no electrical connections to the television set. Such a system should be capable of communicating at a rate sufficient to control an interactive electromechanical device, e.g. an action toy, in real time response to the video program's story line. The system preferably would be compatible with conventional television broadcast, reception and recording equipment and channels. Reception equipment should impose little or no setup time and difficulty, and should be unobtrusive, even while in use. Perhaps most importantly, the system should not unduly burden or distract those viewers who are not using the interactive feature.
Accordingly, it is a principal object of the present invention to provide a video system that enables a remote video broadcast wirelessly to interact with a purchasable educational or entertainment device. Other important objects of the invention include the following:
(1) to provide an interactive video system that is compatible with conventional broadcast equipment and channels, and with conventional television receiving, recording and playback systems, including restricted bandwidth home recording and playback systems;
(2) to provide a system, as described, that minimizes video and audio interference with program material;
(3) to provide a method for subliminally encoding binary data, within the viewing area of a video program image, that is substantially invisible to a viewer of the television;
(4) to provide an interactive video system that easily and unobtrusively may be installed and operated;
(5) to provide interactive video educational and entertainment apparatus that permits the user to interact with a television program in real time;
(6) to provide a method for subliminally, digitally encoding data with a pre-recorded video broadcast;
(7) to provide a method for simplifying the decoder by substantially invisibly removing spurious data from the video input to the encoding apparatus prior to data encoding;
(8) to provide interactive video apparatus that requires no electrical connection to the television and that communicates with one or more purchasable, educational or entertainment devices; and
(9) to provide an interactive video system that is convenient, reliable and inexpensive to use.